The AUR9807 is a single-cell Li-ion charger IC with system power management feature. It charges the battery and power the system simultaneously. The maximum charging current (up to 1.5A) is set by external resistor for fast charging. The output voltage for the system is regulated to a nominal value (three different versions available: 4.4V, 5V or 6V); the actual value of the output voltage depends on the input voltage from the adapter, the charging current and the system loading. With the decrease of the input voltage or the increase of the system loading current, the output voltage drops. When the output voltage drops to a predetermined value (VAPM-REG), the Active Power Management function is activated and tries to maintain the output voltage at VAPM-REG; the AUR9807 will suffice the system loading with first priority and reduce the charging current temporarily, i.e. under heavy load condition, the AUR9807 charges the battery with the remaining available current to keep the output voltage at VAPM. In this manner, the charge and discharge cycle of the battery can be reduced. It is possible that the AUR9807 fails to maintain the output voltage at VAPM-REG; for example, when the system loading current exceeds the capability of the current-limiting AC adapter. In this scenario, the output voltage drops to the battery voltage, and the system is allowed to draw current from the battery.